feat: replace metadata with customMetadata

[julianiff]

This PR adds the customMetadata field to replace the deprecated metadataValues field.

[olivereisenhut]

We should also remove the old metadata in the GQL call and the response interface

[Copilot]

Pull Request Overview

This PR replaces the deprecated metadata field with a new customMetadata field in the API, aligning both the TypeScript type and the GraphQL fragment with the updated data structure.

• Removed duplicate import of version from package.json
• Replaced metadataValues with customMetadata in FrontifyAsset
• Updated GraphQL fragment to use customMetadata instead of metadataValues

Comments suppressed due to low confidence (1)

src/Api.ts:67

• The customMetadata field is defined as an array in the type (customMetadata: { ... }[]) while the GraphQL fragment treats it as a singular object. Verify that the backend schema and resolvers are intended to support an array and update the GraphQL fragment if necessary.

customMetadata: {